Air Pollution and Lung Function
http://www.100md.com
《新英格兰医药杂志》
To the Editor: The pollutants associated with decreased lung growth are largely the result of burning fuels in internal combustion engines and at electrical generating plants. Citing prohibitive costs, the Bush administration favors less stringent regulations than those achievable with the use of maximum emission-control technology and better standards of vehicular fuel efficiency. The administration's position is economically and medically untenable in view of a 2003 report, which did not include the data on air pollution and lung function reported by Gauderman and colleagues (Sept. 9 issue),1 showing that recent rulemaking by the Environmental Protection Agency cost industry about $25 billion and saved about $150 billion in health care costs.2 There is much to learn about the links between air pollution and health. However, we have learned enough to know that it is essential to create the incentives that will enable our nation's scientists and technologists, who are second to none, to help solve this problem in a manner that will lead to continued economic growth, protect the environment, and enhance health.
Alan H. Lockwood, M.D.
University at Buffalo
Buffalo, NY 14215
ahl@buffalo.edu
References
Gauderman WJ, Avol E, Gilliland F, et al. The effect of air pollution on lung development from 10 to 18 years of age. N Engl J Med 2004;351:1057-1067.
Informing regulatory decisions: 2003 report to Congress on the costs and benefits of federal regulations and unfunded mandates on state, local, and tribal entities. Washington, D.C.: Office of Management and Budget, 2003.
To the Editor: Gauderman et al. found a negative, dose-dependent association between various outdoor exposures and lower levels of the forced expiratory volume in one second (FEV1), forced vital capacity, and maximal midexpiratory flow rate in adolescence. However, the conclusion that the growth and development of the lungs are diminished as a result of outdoor pollution during adolescence would seem premature, for several reasons. The correction of measurements of lung function for height might have been more informative, because air pollution also affects growth in height.1 In addition, exposures and disease early in life may contribute most to the level and growth of lung function.2 Furthermore, the use of FEV1 as a substitute for airway size is a considerable simplification, because even normal growth of airway function may not imply normal development.3 Alternatively, normal growth patterns of the airways may be associated with bronchitis-induced airway obstruction (which is common among children who are chronically exposed to outdoor pollutants4). Though the negative effects of outdoor pollutants seem obvious and are worrisome, the interpretation that lung development is diminished can be justified only when the effects are irreversible after the elimination of exposures or with the use of medical interventions. The findings of Gauderman et al. would indeed call for studies of such interventions.
Peter J.F.M. Merkus, M.D., Ph.D.
Sophia Children's Hospital
3000 CB Rotterdam, the Netherlands
References
Jedrychowski W, Maugeri U, Jedrychowska-Bianchi I. Body growth rate in preadolescent children and outdoor air quality. Environ Res 2002;90:12-20.
Johnston IDA, Strachan DP, Anderson HR. Effect of pneumonia and whooping cough in childhood on adult lung function. N Engl J Med 1998;338:581-587.
Silverman M. Inhaled corticosteroids and the growth of lung function in children. Eur Respir J 2004;23:795-796.
Peters JM, Avol E, Navidi W, et al. A study of twelve Southern California communities with differing levels and types of air pollution. I. Prevalence of respiratory morbidity. Am J Respir Crit Care Med 1999;159:760-767.
To the Editor: Gauderman et al. report that air-pollution levels are correlated with pulmonary function in children. The study did not consider two important factors that are related to lung development and pulmonary-function tests: physical activity and obesity.1,2,3 It is possible that children in communities with higher levels of air pollution are less active physically and more likely to be obese than children in communities with lower levels of air pollution. Thus, the conclusion that air pollutants adversely affect pulmonary function in children and adolescents may be incorrect.
Gregory A. Tetrault, M.D.
Memphis Veterans Affairs Medical Center
Memphis, TN 38104
gregory.tetrault@med.va.gov
References
Havryk AP, Gilbert M, Burgess KR. Spirometry values in Himalayan high altitude residents (Sherpas). Respir Physiol Neurobiol 2002;132:223-232.
Gidding SS, Nehgme R, Heise C, Muscar C, Linton A, Hassink S. Severe obesity associated with cardiovascular deconditioning, high prevalence of cardiovascular risk factors, diabetes mellitus/hyperinsulinemia, and respiratory compromise. J Pediatr 2004;144:766-769.
Baltaci G, Ergun N. Maximal oxygen uptake in well-trained and untrained 9-11 year-old children. Pediatr Rehabil 1997;1:159-162.
The authors reply: Drs. Merkus and Tetrault correctly point out that two determinants of respiratory function, height and obesity, must be considered in analyses of the relationship between air pollution and the development of lung function in children. As described in our report, all our analyses were adjusted for both these variables, specifically for annual measurements of height as well as annual measurement of the body-mass index and the square of the body-mass index. Dr. Tetrault further suggests that children in more polluted environments may be less physically active and that less physical activity may be linked to reduced lung function.
To address this concern, we present results showing the effect of adjustment for physical activity on the relationship between air pollution and growth in FEV1 over the eight-year study period (Table 1). Model 1, which is equivalent to the main model shown in Table 4 of our report,1 shows the estimated deficit in the growth in FEV1 over the study period among children exposed to the highest observed levels of acid vapor and elemental carbon, as compared with those exposed to the lowest levels of these pollutants. The model includes adjustment for height, the body-mass index, the square of the body-mass index, and several other variables. As model 2 shows, additional adjustment for an indicator of physical activity — the number of team sports played by the child at study entry — has little effect. It is therefore unlikely that the effects of air pollution on lung function are confounded by the level of physical activity.
Table 1. Sensitivity of the Effects of Pollutants on Growth in FEV1 to Adjustment for Physical Activity over the Eight-Year Study Period.
We agree with Dr. Merkus that further study is warranted to determine whether the effects of air pollution on lung function are irreversible. We have previously shown that changes in exposure to air pollution during adolescence have a measurable effect on the growth of lung function.2 It is still an open question, however, whether the deficits that exist at the age of 18 years, when lung development is nearly complete, are reversible with a change in exposure. To this end, we are following our study subjects beyond high-school graduation and are testing their lung function as young adults. As Dr. Lockwood points out, improving air quality makes economic sense, given the high costs of care associated with pollution-related health outcomes.
W. James Gauderman, Ph.D.
Edward Avol, M.S.
Frank Gilliland, M.D., Ph.D.
University of Southern California
Los Angeles, CA 90089
jimg@usc.edu
References
Gauderman WJ, Avol E, Gilliland F, et al. The effect of air pollution on lung development from 10 to 18 years of age. N Engl J Med 2004;351:1057-1067.
Avol EL, Gauderman WJ, Tan SM, London SJ, Peters JM. Respiratory effects of relocating to areas of differing air pollution levels. Am J Respir Crit Care Med 2001;164:2067-2072.
Alan H. Lockwood, M.D.
University at Buffalo
Buffalo, NY 14215
ahl@buffalo.edu
References
Gauderman WJ, Avol E, Gilliland F, et al. The effect of air pollution on lung development from 10 to 18 years of age. N Engl J Med 2004;351:1057-1067.
Informing regulatory decisions: 2003 report to Congress on the costs and benefits of federal regulations and unfunded mandates on state, local, and tribal entities. Washington, D.C.: Office of Management and Budget, 2003.
To the Editor: Gauderman et al. found a negative, dose-dependent association between various outdoor exposures and lower levels of the forced expiratory volume in one second (FEV1), forced vital capacity, and maximal midexpiratory flow rate in adolescence. However, the conclusion that the growth and development of the lungs are diminished as a result of outdoor pollution during adolescence would seem premature, for several reasons. The correction of measurements of lung function for height might have been more informative, because air pollution also affects growth in height.1 In addition, exposures and disease early in life may contribute most to the level and growth of lung function.2 Furthermore, the use of FEV1 as a substitute for airway size is a considerable simplification, because even normal growth of airway function may not imply normal development.3 Alternatively, normal growth patterns of the airways may be associated with bronchitis-induced airway obstruction (which is common among children who are chronically exposed to outdoor pollutants4). Though the negative effects of outdoor pollutants seem obvious and are worrisome, the interpretation that lung development is diminished can be justified only when the effects are irreversible after the elimination of exposures or with the use of medical interventions. The findings of Gauderman et al. would indeed call for studies of such interventions.
Peter J.F.M. Merkus, M.D., Ph.D.
Sophia Children's Hospital
3000 CB Rotterdam, the Netherlands
References
Jedrychowski W, Maugeri U, Jedrychowska-Bianchi I. Body growth rate in preadolescent children and outdoor air quality. Environ Res 2002;90:12-20.
Johnston IDA, Strachan DP, Anderson HR. Effect of pneumonia and whooping cough in childhood on adult lung function. N Engl J Med 1998;338:581-587.
Silverman M. Inhaled corticosteroids and the growth of lung function in children. Eur Respir J 2004;23:795-796.
Peters JM, Avol E, Navidi W, et al. A study of twelve Southern California communities with differing levels and types of air pollution. I. Prevalence of respiratory morbidity. Am J Respir Crit Care Med 1999;159:760-767.
To the Editor: Gauderman et al. report that air-pollution levels are correlated with pulmonary function in children. The study did not consider two important factors that are related to lung development and pulmonary-function tests: physical activity and obesity.1,2,3 It is possible that children in communities with higher levels of air pollution are less active physically and more likely to be obese than children in communities with lower levels of air pollution. Thus, the conclusion that air pollutants adversely affect pulmonary function in children and adolescents may be incorrect.
Gregory A. Tetrault, M.D.
Memphis Veterans Affairs Medical Center
Memphis, TN 38104
gregory.tetrault@med.va.gov
References
Havryk AP, Gilbert M, Burgess KR. Spirometry values in Himalayan high altitude residents (Sherpas). Respir Physiol Neurobiol 2002;132:223-232.
Gidding SS, Nehgme R, Heise C, Muscar C, Linton A, Hassink S. Severe obesity associated with cardiovascular deconditioning, high prevalence of cardiovascular risk factors, diabetes mellitus/hyperinsulinemia, and respiratory compromise. J Pediatr 2004;144:766-769.
Baltaci G, Ergun N. Maximal oxygen uptake in well-trained and untrained 9-11 year-old children. Pediatr Rehabil 1997;1:159-162.
The authors reply: Drs. Merkus and Tetrault correctly point out that two determinants of respiratory function, height and obesity, must be considered in analyses of the relationship between air pollution and the development of lung function in children. As described in our report, all our analyses were adjusted for both these variables, specifically for annual measurements of height as well as annual measurement of the body-mass index and the square of the body-mass index. Dr. Tetrault further suggests that children in more polluted environments may be less physically active and that less physical activity may be linked to reduced lung function.
To address this concern, we present results showing the effect of adjustment for physical activity on the relationship between air pollution and growth in FEV1 over the eight-year study period (Table 1). Model 1, which is equivalent to the main model shown in Table 4 of our report,1 shows the estimated deficit in the growth in FEV1 over the study period among children exposed to the highest observed levels of acid vapor and elemental carbon, as compared with those exposed to the lowest levels of these pollutants. The model includes adjustment for height, the body-mass index, the square of the body-mass index, and several other variables. As model 2 shows, additional adjustment for an indicator of physical activity — the number of team sports played by the child at study entry — has little effect. It is therefore unlikely that the effects of air pollution on lung function are confounded by the level of physical activity.
Table 1. Sensitivity of the Effects of Pollutants on Growth in FEV1 to Adjustment for Physical Activity over the Eight-Year Study Period.
We agree with Dr. Merkus that further study is warranted to determine whether the effects of air pollution on lung function are irreversible. We have previously shown that changes in exposure to air pollution during adolescence have a measurable effect on the growth of lung function.2 It is still an open question, however, whether the deficits that exist at the age of 18 years, when lung development is nearly complete, are reversible with a change in exposure. To this end, we are following our study subjects beyond high-school graduation and are testing their lung function as young adults. As Dr. Lockwood points out, improving air quality makes economic sense, given the high costs of care associated with pollution-related health outcomes.
W. James Gauderman, Ph.D.
Edward Avol, M.S.
Frank Gilliland, M.D., Ph.D.
University of Southern California
Los Angeles, CA 90089
jimg@usc.edu
References
Gauderman WJ, Avol E, Gilliland F, et al. The effect of air pollution on lung development from 10 to 18 years of age. N Engl J Med 2004;351:1057-1067.
Avol EL, Gauderman WJ, Tan SM, London SJ, Peters JM. Respiratory effects of relocating to areas of differing air pollution levels. Am J Respir Crit Care Med 2001;164:2067-2072.